ELECTRONIC HOUSING WITH ELECTRONIC BOARDS COMPRISING HEAT PIPES
The field of the invention is that of the discharge of heat from electronic cards in operation and more specifically from electronic devices comprising at least one heat pipe. The electronic package according to the invention comprises at least a mechanical structure comprising at least one housing, an electronic card, and means for mechanically attaching the electronic card in the housing of the structure, the electronic card comprising at least one electronic component and a device of high thermal conductivity joined to the electronic card and comprising two ends, the first end being in thermal contact with the electronic component and the second end of the device of high thermal conductivity being mechanically arranged so as to ensure good thermal contact with the walls of the housing of the structure.
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The present Application is based on International Application No. PCT/EP2007/061101, filed on Oct. 17, 2007, which in turn corresponds to French Application No. 06 09300, filed on Oct. 24, 2006 and priority is hereby claimed under 35 USC §119 based on these applications. Each of these applications are hereby incorporated by reference in their entirety into the present application.
BACKGROUND OF THE INVENTION1. Filed of the Invention
The field of the invention is that of the discharge of heat from electronic cards in operation and more specifically from electronic devices comprising at least one heat pipe.
2. Description of the Invention
The components of electronic cards dissipate a large amount of heat, causing a significant increase in the temperature of associated components and electronic circuits. This rise in temperature may reach several tens of degrees. It is all the larger as for some professional applications the electronic cards are situated in an environment already at a raised temperature. This is the case for some aeronautical or defense applications. However, the characteristics, the reliability and the lifetime of a large number of electronic components depend greatly on the temperature. It is therefore vital for the security of operation of an electronic device that the heat is controlled and discharged in proper conditions.
It is known that heat transfer can be produced by:
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- thermal radiation. A hot body naturally emits thermal radiation. This emission is not enough to allow effective discharge of the heat.
- thermal convection. When the hot body is in contact with moving gas or liquid fluids, part of the thermal energy is transferred to the fluid. For the convection to be effective, it is preferable that the circulation of the fluid is forced so as to optimize the heat exchange. Consequently, means for pumping and discharging the fluid are necessary. For example, when the fluid is a gas, forced ventilation is brought about by means of fans.
- thermal conduction: this takes place between two bodies at different temperatures connected to one another by a solid, liquid or gas substance in which the thermal energy is propagated due to inelastic impacts between molecules.
The discharge of heat by thermal conduction is preferred when, due to problems of weight, bulk, sealing and cost, the possibility does not exist of using thermal convection which necessitates particular means of heat extraction and discharge. This is the mode of discharge adopted for a certain number of electronic computers and notably computers on board aircraft.
In order to discharge heat, it is possible to use heat pipes. A heat pipe is a closed system that makes it possible, by benefitting from phase changes of a coolant, to remove heat from one location and to redistribute it at another. Its operation is shown diagrammatically in
There are various possibilities for fitting heat pipes to an electronic package. They are illustrated in
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- the electronic component 1 to be cooled is represented by a black rectangle;
- the electronic card 2 which bears this component 1 is represented by a rectangle comprising a first dotted pattern;
- the electronic package 3 which bears the electronic card 2 is represented by an outline with two lines;
- the parts 4 that ensure the thermal junction between the heat pipe 10 and the other parts comprise a second dotted pattern.
In a first embodiment illustrated in
In a second embodiment illustrated in
In a third embodiment, illustrated in
The device according to the invention make it possible to eliminate the various drawbacks of these embodiments.
More precisely, the subject of the invention is an electronic package comprising at least:
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- a mechanical structure comprising at least one housing,
- an electronic card, and
- means for mechanically attaching the electronic card in the housing of said structure,
- the electronic card comprising at least one electronic component and a device of high thermal conductivity comprising two ends, the first end being in thermal contact with said electronic component, characterized in that the second end of the device of high thermal conductivity is mechanically arranged so as to ensure good thermal contact with the walls of the housing of the structure.
Advantageously, the electronic card comprises an interface part situated between the walls of the housing and the second end of the device of high thermal conductivity.
Advantageously, the housing of the structure has the form of a straight groove with a U-shaped cross section.
Advantageously, the means for mechanically attaching the electronic card are wedge retainer devices, also known as card-lock retainers or wedge-lock retainers.
Advantageously, the device of high thermal conductivity is a heat pipe comprising an evaporator part and a condenser part, the first end corresponding to the evaporator part and the second end corresponding to the condenser part of said heat pipe.
Still other objects and advantages of the present invention will become readily apparent to those skilled in the art from the following detailed description, wherein the preferred embodiments of the invention are shown and described, simply by way of illustration of the best mode contemplated of carrying out the invention. As will be realized, the invention is capable of other and different embodiments, and its several details are capable of modifications in various obvious aspects, all without departing from the invention. Accordingly, the drawings and description thereof are to be regarded as illustrative in nature, and not as restrictive.
The present invention is illustrated by way of example, and not by limitation, in the figures of the accompanying drawings, wherein elements having the same reference numeral designations represent like elements throughout and wherein:
The invention is based on the two following observations:
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- the device of high thermal conductivity that enables the discharge of the heat dissipated by the electronic component(s) of the card must be joined to this so as to permit straightforward mounting and dismounting;
- this device must be connected to the electronic package so as to enable effective discharge of the heat.
To meet these constraints, the devices of high thermal conductivity according to the invention are on the one hand joined to the electronic card and on the other hand are positioned such that one of their ends is situated in the housing of the structure ensuring that the electronic card is retained in its package.
By way of nonlimiting example,
In the case of
The electronic card 2 comprises at least one hot component 1 which is intended to be cooled.
The evaporator part of the heat pipe 10 is positioned on this electronic component 1. Optionally, to ensure better thermal conduction, the attachment of the heat pipe to the component may be ensured by means of a transfer part 24 in which the evaporator part of the heat pipe 10 is attached. This transfer part 24 is attached to the component by means of a heat-conducting thermal grease.
The electronic package 3 comprises a mechanical structure that is generally a good conductor of heat. This mechanical structure comprises at least one housing 30 in which the electronic card 2 is housed. Mechanical attachment means 9 ensure that the electronic card 2 is retained in its housing 30.
The condenser part of the heat pipe 10 is positioned so as to ensure good thermal contact with the walls of the housing 30 of the structure. Here again, as can be seen in
Generally, the electronic cards are slid into housings in the form of a straight groove with a U-shaped cross section. In this case the means of mechanical attachment may be wedge retainer devices, better known under the brand “card-ok retainers” marketed by the company Calmark, or “wedge-lock retainers” marketed by the company Birtcher. The working principle of these wedge devices is shown in
When the heat pipe is in the form of a tube, it is possible to bend the tube so that the bent part matches the groove. In this way, the heat exchange surface area between the heat pipe and the electronic package is increased.
It should also be noted that this fitting of the heat pipe makes it possible to leave free the largest fitting surface for electronic components on the card.
Finally, in this arrangement the heat pipe also serves as a mechanical stiffener of the electronic card.
It will be readily seen by one of ordinary skill in the art that the present invention fulfils all of the objects set forth above. After reading the foregoing specification, one of ordinary skill in the art will be able to affect various changes, substitutions of equivalents and various aspects of the invention as broadly disclosed herein. It is therefore intended that the protection granted hereon be limited only by definition contained in the appended claims and equivalents thereof.
Claims
1. An electronic package comprising:
- a mechanical structure having a housing,
- an electronic card, and
- means for mechanically attaching the electronic card in the housing of said structure,
- the electronic card having an electronic component and a device of high thermal conductivity joined to the electronic card and having two ends, both joined to the electronic card, the first end being in thermal contact with said electronic component, wherein the second end of the device of high thermal conductivity is mechanically arranged so as to ensure good thermal contact with the walls of the housing of the structure.
2. The electronic package as claimed in claim 1, wherein the electronic card comprises an interface part situated between the walls of the housing and the second end of the device of high thermal conductivity.
3. The electronic package as claimed in claim 1, wherein the housing of the structure has the form of a straight groove with a U-shaped cross section.
4. The electronic package as claimed in claim 1, wherein the means for mechanically attaching the electronic card are wedge retainer devices, also known as card-lock retainers or wedge-lock retainers, each wedge essentially comprising several wedges of trapezoidal shape arranged head-to-foot so as to form a single wedge with the shape of an elongate parallelepiped and a central screw that passes through the assembly of wedges so as to hold them together.
5. The electronic package as claimed in claim 1, wherein the device of high thermal conductivity is a heat pipe comprising an evaporator part and a condenser part, the first end corresponding to the evaporator part and the second end corresponding to the condenser part of said heat pipe.
Type: Application
Filed: Oct 17, 2007
Publication Date: Jan 7, 2010
Applicant: THALES (Neuilly Sir Seine)
Inventors: Pierre Bertrou (Merignac), Catherine Lavergne (Talence), Stephane Poveda (Merignac)
Application Number: 12/446,640
International Classification: H05K 7/20 (20060101);